Axios + axios-retry with exponential backoff, tested with nock: working versions (tested 2026-10-15)

{
  "name": "axios-retry-nock",
  "private": true,
  "type": "module",
  "scripts": {
    "test": "node --import tsx --test test/*.test.ts"
  },
  "dependencies": {
    "axios": "1.20.0",
    "axios-retry": "4.5.0"
  },
  "devDependencies": {
    "tsx": "4.23.15",
    "@types/node": "24.19.2",
    "nock": "15.0.1"
  }
}

import axios, { type AxiosError } from "axios";
import axiosRetry, { isNetworkOrIdempotentRequestError } from "axios-retry";

export function createClient(baseURL: string, retries = 3) {
  const client = axios.create({ baseURL, timeout: 5000 });
  axiosRetry(client, {
    retries,
    retryDelay: (n) => (process.env.NODE_ENV === "test" ? 0 : axiosRetry.exponentialDelay(n)),
    retryCondition: (err: AxiosError) => isNetworkOrIdempotentRequestError(err) || err.response?.status === 429,
  });
  return client;
}

import { test, afterEach } from "node:test";
import assert from "node:assert/strict";
import nock from "nock";
import { createClient } from "../src/client.ts";

process.env.NODE_ENV = "test";
const BASE = "https://api.example.com";
afterEach(() => nock.cleanAll());

test("retries 503 then succeeds", async () => {
  nock(BASE).get("/items").reply(503).get("/items").reply(503).get("/items").reply(200, [{ id: 1 }]);
  const res = await createClient(BASE).get("/items");
  assert.deepEqual(res.data, [{ id: 1 }]);
  assert.equal(res.config["axios-retry"]?.retryCount, 2);
});

test("retries 429", async () => {
  nock(BASE).get("/items").reply(429).get("/items").reply(200, []);
  assert.equal((await createClient(BASE).get("/items")).status, 200);
});

test("does not retry non-idempotent POST on 500", async () => {
  const scope = nock(BASE).post("/items").reply(500);
  await assert.rejects(createClient(BASE).post("/items", {}));
  assert.ok(scope.isDone());
});

test("gives up after the retry limit", async () => {
  nock(BASE).get("/items").times(3).reply(500);
  await assert.rejects(createClient(BASE, 2).get("/items"), (e: any) => e.response.status === 500);
});